public bool TryGet(string key, out WindowsAuthenticationHandshake handshake)
        {
            bool result = false;
            handshake = null;

            if (handshakeCache.Contains(key))
            {
                object cachedHandshake = handshakeCache[key];
                if (cachedHandshake != null)
                {
                    handshake = cachedHandshake as WindowsAuthenticationHandshake; 
                    result = true;
                }
            }

            return result;
        }
 public void Add(string key, WindowsAuthenticationHandshake handshake)
 {
     handshakeCache.Set(key, handshake, GetCacheItemPolicy());
 }